Analysis of Delta pH and the xanthophyll cycle in NPQ of the Antarctic sea ice alga Chlamydomonas sp ICE-L

作者：Mou, Shanli; Zhang, Xiaowen; Ye, Naihao^*; Miao, Jinlai; Cao, Shaona; Xu, Dong; Fan, Xiao; An, Meiling

来源：Extremophiles, 2013, 17(3): 477-484.

DOI：10.1007/s00792-013-0532-x

• Delta pH
• Xanthophyll cycle
• NPQ
• Antarctic sea ice alga
• Chlamydomonas sp ICE-L

Non-photochemical fluorescence quenching (NPQ) is mainly associated with the transthylakoid proton gradient (Delta pH) and xanthophyll cycle. However, the exact mechanism of NPQ is different in different oxygenic photosynthetic organisms. In this study, several inhibitors were used to study NPQ kinetics in the sea ice alga Chlamydomonas sp. ICE-L and to determine the functions of Delta pH and the xanthophyll cycle in the NPQ process. NH4Cl and nigericin, uncouplers of Delta pH, inhibited NPQ completely and zeaxanthin (Z) was not detected in 1 mM NH4Cl-treated samples. Moreover, Z and NPQ were increased in the samples containing N,N'-dicyclohexyl-carbodiimide (DCCD) under low light conditions. We conclude that Delta pH plays a major role in NPQ, and activation of the xanthophyll cycle is related to Delta pH. In dithiothreitol (DTT)-treated samples, no Z was observed and NPQ decreased. NPQ was completely inhibited when NH4Cl was added suggesting that part of the NPQ process is related to the xanthophyll cycle and the remainder depends on Delta pH. Moreover, lutein and beta-carotene were also essential for NPQ. These results indicate that NPQ in the sea ice alga Chlamydomonas sp. ICE-L is mainly dependent on Delta pH which affects the protonation of PSII proteins and de-epoxidation of the xanthophyll cycle, and the transthylakoid proton gradient alone can induce NPQ.

• 出版日期2013-5
• 单位中国水产科学研究院; 青岛农业大学; 国家海洋局第一海洋研究所